Broadband over power lines (BPL)

High-speed Internet access anywhere, anytime—that's what we've increasingly come to expect in the 21st-century information age. But what if you live in a rural area where it's too expensive for a telecoms company to provide broadband? Or what if your house has old telephone wiring or the room you want to work in doesn't have a telephone access point? Worry not! The solution could be BPL (broadband over power lines), also called EOP (Ethernet over power)—a way of piping broadband to your home and channeling it from one room to another using the standard electricity supply. BPL is also known as HomePlug (the name of an alliance of manufacturers who make the equipment) and, in the UK, as "networking over the mains." Let's take a closer look at how it works!

Sending two signals down one line

If you know something about broadband Internet already, you're probably aware that it works by splitting your ordinary telephone line into a number of separate channels. Some of them carry your phone calls, as usual, some carry downloads (information coming from the Internet to your home), and some handle uploads (information going the opposite way). Broadband uses low-frequency electric signals (the equivalent of low-pitched sounds) to carry ordinary phone calls and higher-frequency signals (like high-pitched sounds) to carry Internet data. Electronic filters separate the two kinds of signal, with the low frequencies going to your telephone and the higher frequencies to your Internet modem.

Access BPL: bringing broadband to your home

If you can send computer data down a phone line, there's no reason why you can't channel it down a power line as well. Some Internet service providers (ISPs) are already using overhead and underground power lines to carry broadband data long distances to and from their customers in what's called access BPL. It's exactly the same principle as sending broadband over a phone line: a high-frequency signal carrying the broadband data is superimposed on the lower-frequency, alternating current that carries your ordinary electric power. In your home, you need to have slightly modified power outlets with an extra computer socket. Plug in a special BPL modem, plug that into your computer, and your broadband is up and running in no time.

In-house BPL: carrying broadband within your home

You can also use BPL with traditional telephone or cable broadband to bring Internet access to all the different rooms in your home. You simply plug the Ethernet lead from your normal modem into a special adapter that fits into one of the power outlets. Your home electricity circuit then takes the broadband to and from every room in your house as a high-frequency signal superimposed on top of the power supply. If you want to use broadband in a bedroom, you simply plug another Ethernet adapter into one of the ordinary power outlets in that room and plug your computer into it. In-house BPL, as this system is known, is a great way of getting broadband in any part of your home. It's particularly useful if you have a big house with thick walls that make wireless Internet impossible.

Smart homes of the future?

BPL opens up an even more exciting possibility for the future. If we can connect computers using the ordinary power lines in our home, there's nothing to stop us connecting up domestic appliances both to one another and to the Internet. Smart homes (in which appliances are switched on and off automatically by electronic controllers or computers) have used this basic idea for years—but BPL could take it much further and make it far more widespread. Imagine a future where you can use a Web browser on your computer at work to switch on the electric cooker in the kitchen at home, ready for when you arrive.

Advantages

• Electricity power lines are ubiquitous in most developed countries.
• Access BPL may be quicker, cheaper, and simpler to deploy in rural areas than higher cost, high-speed broadband over telephone lines or cable.
• Access BPL technology is relatively simple.
• Power companies who already supply electricity could also provide inexpensive broadband to existing customers over the same lines, which could help to push down the cost of broadband across the board.
• In-house BPL is perfectly compatible with Wi-Fi and helps to overcome distance and reliability limitations in existing wired and wireless networks.

Disadvantages

• Access BPL is still relatively uncommon. At the time of writing, it's failed to gain momentum in countries such as the United States, the UK, and Australia. In-house BPL is much more popular, however, and still widely available.
• Only low and medium voltage power cables can be used for access BPL.
• Different countries use different power voltages, which would make it harder to sell equipment internationally and push up the cost.
• Signals need booster equipment to make them travel long distances. Transformers, circuit breakers, and surge protectors can interfere with broadband signals.
• Most people already use DSL (traditional broadband) or wireless systems and own routers, modems, and other equipment compatible with it. They'll be reluctant to buy new equipment unless there's a compelling reason to do so.